The World Wide Web (“web”) uses the client-server model to communicate information between clients and servers. Web servers are coupled to the Internet and respond to document requests from web clients. Web clients (e.g., web “browsers”) are programs that allow a user to simply access web documents located on web servers.
An example of a client-server system interconnected through the Internet may include a remote server system interconnected through the Internet to a client system. The client system may include conventional components such as a processor, a memory (e.g., RAM), a bus which coupled the processor and memory, a mass storage device (e.g., a magnetic hard disk or an optical storage disk) coupled to the processor and memory through an I/O controller and a network interface, such as a conventional modem. The server system also may include conventional components such as a processor, memory (e.g., RAM), a bus which coupled the processor and memory, a mass storage device (e.g., a magnetic or optical disk) coupled to the processor and memory through an I/O controller and a network interface, such as a conventional modem.
To define the addresses of resources on the Internet, Uniform Resource Locator (URL) system are used. A URL is a descriptor that specifically defines a type of Internet resource and its location. To access an initial web document, the user enters the URL for a web document into a web browser program. Then, a request is made by a client system, such as a router or other network device, and is sent out over the network to a web server. Thus, the web browser sends a request to the server that has the web document using the URL. The web server responds to the request and sends the desired content back over the network to the requester. For example, the web server responds to the http request by sending the requested object to the client. In many cases, the object is an plain text (ASCII) document containing text (in ASCII) that is written in HyperText Markup Language (HTML); however, the object may be video clip, movie or other high quality content.
A problem with the Internet is that it has limited bandwidth resources and different points in the Internet may experience network congestion, resulting in poor performance especially for bandwidth-intensive applications. Internet backbone is often pairfully to slow. The bandwidth limitation is mainly due to one or more congested links between the web server and the client. Broadband access can help but does not help if the congestion occurs deeper in the network.
One prior art solution to accommodate the slowness of the Internet backbone is to move content closer to individuals desiring the content. To that end, content may be cached on the carrier edge and requests for such content may be serviced from these caches, instead of the web server servicing the requests. Distributing content in this manner can require large numbers of cache memories being deployed at the carrier edge and each cache memory stores content from a number of sites. When a request is made for content from a site that has been stored in one (or more) of the cache memories that is closer to the requester than the original website, the request is satisfied from the cache. In such a situation, the interactive experience is improved significantly only if content from the site has been stored in the cache and the individual making the request is close enough to one of the servers supporting such a cache to satisfy requests with the content stored therein. This is referred to as carrier edge caching. One provider of such a service is Akamai. Also, such an arrangement for caching content requires that the content owner and the entity caching the content enter an agreement with respect to the access for that content so that the content can be stored ahead of time.
Even if using content distribution, the link between the point of access to the network for the content requester may remain a bottleneck for applications requiring very large amounts of bandwidth, such as high quality video.